The present invention relates generally to tailor welded blank forming. More specifically, the present invention relates to the design of a vehicle door utilizing three-piece tailor welded blank forming.
During the past two decades, governmental fuel conservation and safety mandates along with global competition and environmental concerns have prompted the automotive industry to design lighter vehicles for reduced fuel consumption and reduced manufacturing costs, while improving the overall structure of the vehicle for occupant safety.
A relatively new process known as tailor welded blank forming has been developed in an attempt to meet these needs. The tailor welded blank forming process replaces the traditional sequential forming then welding process with a sequential welding then forming process. The tailor welded blank forming process involves joining various metal sheet sections (e.g. steel sheets) having different properties, such as thickness, strength, etc., into a single welded blank for subsequent forming operations to a desired shape. Therefore, optimum material properties can be located precisely within the formed part where needed for particular applications.
For example, thicker and/or stronger sheet material is typically used at locations that previously required reinforcement parts. The potential benefits of the tailor welded blank forming process include fewer parts, fewer forming dies, fewer spot welds, less material input, and better utilization of sheet metal. Consequently, use of tailor welded forming processes will typically result in weight reduction, improved structural integrity, reduced scrap, lower manufacturing costs, and improved dimensional accuracy.
Tailor welded blank technology has recently been utilized in the automotive industry. Specifically, a few automotive manufacturers have recently started using two piece tailor welded blank forming for vehicle doors in place of the current conventional door forming process in order to provide a thicker structure at some of the more sensitive areas.
FIG. 1 is an illustration of a vehicle door constructed from known two-piece tailor welded blank (TWB) forming. The two-piece TWB vehicle door 10 includes a first side portion, a second side portion 14 opposing the first side portion 12, and a bottom side portion 16 connecting the bottom end 18 of the first side portion 12 to the bottom end 20 of the second side portion 14. The first side portion 12 has an upper end 22 opposing the lower end 18, with the upper end 22 being connected to an inclined upper portion 24. The inclined upper portion 24 is connected to a top side portion 26, which in turn is connected to the upper end 28 of the second side portion 14.
The vehicle door 10 has a first section 32 and a second section 34. The first section 32 is formed such that it encompasses the first side portion 12. The vehicle door hinges are attached to the door along the first side portion 12 and thus, this area of the door 10 is subjected to significant stress. In prior conventional designs, the area where the hinges 36 attached to the door was typically formed with reinforcing structures to provide additional strength characteristics to compensate for the stress to which the area is subjected. Accordingly, with known prior two-piece TWB designs, the first section 32 is constructed of a thicker gage material in order to reduce the need for reinforcing ribs or other structures to provide strength to the door area adjacent the hinges.
The second section 34, which is welded to the first section 32 prior to forming the door structure, is formed of a lighter gage material than the first section 32. The configuration of the two-piece TWB door design provides the necessary strength at the door hinge side of the door while at the same time reducing the weight of the overall door. This configuration while beneficial, still does not provide optimum performance in all areas.
It is an object of the present invention to provide a vehicle door structure formed from three-piece tailor welded blank forming that provides improved system performance in a variety of different measurable areas over prior vehicle door designs.
It is another object of the present invention to provide a vehicle door structure formed from three-piece tailor welded blank forming that provides decreased overall weight as compared to prior conventional vehicle door designs.
It is still another object of the present invention to provide a vehicle door structure formed from three-piece tailor welded blank-forming that provides reduced design cost as compared to prior conventional vehicle door designs.
In accordance with the above and other objects of the present invention, a vehicle door structure formed from three-piece tailor welded blank forming is provided. The vehicle door includes a bottom side portion and a pair of opposing generally vertical side portions. The first generally vertical side portion is located adjacent the door hinges. The second generally vertical side portion is located adjacent the door handle. The first generally vertical side portion has an upper portion that is attached to a generally inclined upper portion. The generally inclined upper portion is also attached to a top side portion, which is attached to an upper portion of the second vertical side portion. The vehicle door includes a panel portion which is generally defined by the bottom side portion, the first generally vertical side portion, the lower portion of the second generally vertical side portion, and a lower window frame portion.
The vehicle door has a first thicker gage portion that covers essentially all of the primary bone structure that results from the attachment and location of the door hinges. The vehicle door has a second thicker gage portion that covers essentially all of the primary bone structure that results from the attachment and location of the door latch. A thinner gage portion is disposed between the first thicker gage portion and the second thicker gage portion such that the overall weight of the door is reduced.
These and other features of the present invention will become apparent from the following description of the invention, when viewed in accordance with the accompanied drawings and appended claims.